What is muscular dystrophy?
Muscular dystrophy is a group of rare diseases that cause muscle weakness. All types of muscular dystrophy get worse over time and can cause problems with walking and other daily activities. Some types of muscular dystrophy can also cause problems with breathing and heart muscle involvement.
Muscular dystrophy is caused by a genetic mutation that children are born with. There is no cure, but treatment can prevent complications and help with symptoms.
There are more than 30 different types of muscular dystrophy. Some start in childhood while others don’t appear until adulthood. The two most common types of muscular dystrophy that affect children are Duchenne muscular dystrophy and Becker muscular dystrophy.
The different types of muscular dystrophy vary by who is most likely to get them, which muscles they affect, and how quickly they progress.
Lucas receives gene therapy for DMD and finds his super muscles
The first patient in the state to receive a new gene therapy is a trailblazer for children with Duchenne muscular dystrophy.
Muscular Dystrophy | Symptoms & Causes
What are the symptoms of muscular dystrophy?
The most common symptom of all types of muscular dystrophy is muscle weakness that gets worse over time.
Each type of muscular dystrophy has its own specific symptoms.
Duchenne muscular dystrophy (DMD)
DMD is the most common and most severe form of childhood muscular dystrophy and most often affects boys. Symptoms usually begin between the ages of 2 and 5 and progress quickly. The symptoms include:
- Frequent falls
- Trouble getting up from a lying or sitting position
- Waddling walk
- Difficulty running and jumping
- Delayed growth
Becker muscular dystrophy
Becker muscular dystrophy is similar to DMD, but symptoms usually appear during adolescence and progress more slowly. It almost always affects boys. Symptoms include:
- Walking on tiptoes
- Frequent falls
- Muscle cramping
Emery-Dreifuss muscular dystrophy
Most common in boys, this type of muscular dystrophy causes weakness and progressive wasting of the lower leg and upper arm muscles. Symptoms include:
- Muscle weakness that begins in the upper arms and lower legs
- Decreased movement in the spine, knees, elbows, ankles, and back of neck
- Elbows locked in a flexed position
- Rigid spine
Limb-girdle muscular dystrophy
Affects both boys and girls. Symptoms usually begin between the ages of 5 and 15 and include:
- Weakness around the hips that spreads to the legs, shoulders, and neck
- Frequent falls
- Waddling when walking
- Rigid spine
Facioscapulohumeral muscular dystrophy
This type affects muscles in the face, upper arms, and shoulders. Symptoms usually appear in adolescence and may include:
- Weakness in the facial muscles and shoulders
- Trouble drinking from a straw or smiling
- Dry eyes
- Slanted shoulders or a winged appearance of the shoulder blades
Distal muscular dystrophy
Also called distal myopathy, this type of muscular dystrophy affects muscles in the lower arms, legs, hands, and feet. Symptoms are less severe and usually progress slowly. They include:
- Trouble with hand movements and extending the fingers
- Difficulty walking and climbing stairs
- Inability to stand on the heels or hop
Myotonic dystrophy
The most common type of muscular dystrophy in adults with symptoms that sometimes begin in early childhood or soon after birth (congenital myotonic dystrophy). Symptoms in infants include:
- Trouble swallowing or breathing
- Lack of reflexes
- Muscle weakness in the face
- Delayed motor skills
What are the causes of muscular dystrophy?
Muscular dystrophy is caused by a mutation in one of the genes that affects proteins in the muscles. This mutation causes proteins to be missing or altered so they don’t work correctly. Over time, the muscles break down and become weak. Each type of muscular dystrophy is caused by a different mutation.
Most of the time, children are born with the genetic mutation that causes muscular dystrophy. But in some cases, the mutation occurs spontaneously. In this case, the mutation can then be passed on future generations.
Muscular Dystrophy | Diagnosis & Treatments
How is muscular dystrophy diagnosed?
The first step in diagnosing muscular dystrophy is a complete exam and medical history. Based on these findings, the clinician may order one of more of the following tests to help diagnose muscular dystrophy and to determine which type the child has.
- Blood tests to measure certain enzymes that may indicate muscle damage
- Muscle biopsy to check the muscle tissue for muscle disease
- Imaging tests, such as magnetic resonance imaging (MRI) or ultrasound to check muscle quality
- Neurological tests to rule out other conditions and to test coordination and reflexes
- Genetic testing to look for mutations that could signal a specific type of muscular dystrophy
How is muscular dystrophy treated?
Children with muscular dystrophy should have regular visits with their care team so any changes in their health can be detected early.
Most treatments for muscular dystrophy focus on slowing the progression of the disease and easing symptoms. These can vary from patient to patient, depending on the type of muscular dystrophy they have and how much it has progressed.
These treatments may include:
- Physical therapy to help keep muscles strong and flexible.
- Occupational therapy to develop skills needed for independence at home, school, and in the community.
- Speech therapy to improve communication skills and address swallowing problems in children with muscle weakness in the face.
- Respiratory therapy to help with breathing.
- Steroids and other medications are sometimes used for Duchenne muscular dystrophy.
- Heart medicines to manage the effects of muscular dystrophy on the heart.
In some cases, surgery may help manage complications of muscular dystrophy. For instance, surgery to implant a pacemaker can help with heart problems, surgery to remove cataracts can reduce vision problems, while spine surgery can address spinal curvature.
Gene therapy
In June 2023, the FDA approved a gene therapy for patients with DMD between 4 and 5 years old who meet certain criteria. This treatment addresses the underlying cause of DMD by enabling the body to make a protein similar to dystrophin, the protein that DMD inhibits. Learn more about gene therapy and contact gene.therapy@childrens.harvard.edu for more information.
How we care for muscular dystrophy
The Department of Neurology works with specialists from many different areas of Boston Children’s Hospital to treat our patients with muscular dystrophy. Depending on the type of muscular dystrophy your child has and its severity, their team may include specialists in physical therapy, rehabilitation medicine, orthopedic surgery, cardiology, pulmonology, feeding and swallowing, and genetics. This team works closely with patients and their families to tailor treatment as children’s health and needs change over time.
In addition to caring for children with muscular dystrophy, Boston Children’s Hospital is committed to research to better understand and manage these diseases. Many of the genes responsible for muscular dystrophies and other neuromuscular disorders were found at Boston Children’s Neuromuscular Center. The researchers who made these discoveries continue to learn more and develop treatments. We are also one of a few sites in the United States funded by the National Institutes of Health (NIH) and various sponsors to conduct clinical studies on muscular dystrophy.
